Quick Summary
A cavity is a hole caused by decay and it will not heal on its own once it forms. Small cavities are treated with a quick, numbed filling in one visit. Early treatment prevents deeper decay that could need a root canal, crown or extraction.
How Does a Cavity Form?
A cavity is a hole in a tooth caused by decay. It starts when bacteria in plaque feed on sugars and starches from food and drink and produce acid. That acid slowly dissolves the hard outer enamel. Every time you eat or sip something sweet, your teeth face an acid attack that lasts for around half an hour.
This is why how often you have sugar matters as much as how much. Sipping sweet tea or coffee through the day, or grazing on biscuits and sweets, keeps your teeth under near-constant attack.
From a White Spot to a Toothache: The Stages of Decay
| Stage | What is happening | Typical treatment |
|---|---|---|
| Early demineralisation | Enamel is losing minerals. You may see a chalky white spot. There is no hole yet. | Fluoride, better brushing and diet changes, and monitoring. This stage can sometimes be reversed |
| Enamel and dentine cavity | A hole has formed and is spreading into the softer layer beneath the enamel. | Removal of decay and a filling |
| Deep cavity | Decay is close to the nerve. Sensitivity to hot, cold or sweet may linger. | A larger filling, or in some cases a root canal |
| Infected nerve or abscess | Severe throbbing pain, swelling or a pimple-like bump on the gum. | Root canal treatment or extraction |
Signs You May Have a Cavity
- Sensitivity to sweet, hot or cold food and drink.
- A visible dark spot, brown stain or hole on a tooth.
- Pain when you bite down, or a dull ache that comes and goes.
- Food that keeps catching in the same spot between your teeth.
- A rough edge or a piece of tooth that has chipped away.
Many cavities cause no symptoms at all until they are quite deep. That is why regular check-ups and X-rays matter: your dentist can find decay long before you feel it.
Types of Dental Fillings
The right material depends on the location and size of the cavity, how much of the tooth remains and how you bite. Your dentist will recommend the best option for your tooth. These are the main types in general use:
| Material | Key features | Consider |
|---|---|---|
| Tooth-coloured composite | Matches your natural shade and bonds to the tooth, so less healthy tooth needs to be removed. | Good for front and back teeth. Needs careful placement to last well |
| Glass ionomer | Releases fluoride and bonds to the tooth. Often used near the gumline and in children. | Less wear-resistant, so usually chosen for low-pressure areas |
| Amalgam (silver) | A long-established, durable filling for back teeth. | Visible silver colour and less commonly chosen today |
Most patients today prefer tooth-coloured fillings because they blend in. If your tooth is badly broken down, a filling may not be strong enough and a crown may be the better long-term choice.
What Happens During a Filling
A filling is a quick, routine procedure and is usually completed in a single visit.
Diagnosis
We examine the tooth and, where needed, take an X-ray to see how deep the decay goes.
Numbing and cleaning
The area is numbed. The decayed part of the tooth is carefully removed and the cavity cleaned.
Placing the filling
The material is placed in layers and set with a special light so it hardens quickly.
Bite check and polish
We shape and polish the filling and check that your bite feels natural.
Sensitive tooth or a dark spot?
A simple check-up can catch a cavity early, while it is still a small filling. Book your visit at our Velachery clinic.
After Your Filling: What to Expect
- Wait until the numbness wears off before eating or drinking anything hot, to avoid biting your cheek or tongue.
- Mild sensitivity for a few days to hot, cold or pressure is common and usually settles.
- Tell us if your bite feels high or the sensitivity is getting worse. A quick adjustment often fixes it.
- Brush and floss as usual. Fillings can still get decay around the edges.
How to Prevent New Cavities
- Brush for two minutes twice a day with a fluoride toothpaste, and do not rinse with lots of water straight afterwards.
- Clean between your teeth once a day. Many cavities start in the tight spaces between teeth.
- Cut down how often you have sugar, especially sweet tea, coffee, soft drinks, sweets and sticky snacks between meals.
- Visit your dentist every six months for a check-up and cleaning.
- Ask about sealants and fluoride for children. Read our guide to kids dental care.
Why Waiting Makes Cavities More Expensive
A small cavity is a simple filling. Left alone, decay keeps growing. It can reach the nerve, at which point you may need a root canal and a crown, and eventually an extraction and replacement. Treating decay early is almost always kinder to your teeth and your wallet. You can read more on our dental fillings page.
Frequently Asked Questions
The tooth is numbed first, so you should not feel pain. You may feel pressure and hear the drill. If you feel anything sharp, tell us and we will top up the anaesthetic.
Very early enamel damage, before a hole forms, can be reversed with fluoride and better habits. Once there is an actual cavity, it will not heal and needs a filling.
Wait until the numbness has fully gone, usually a couple of hours. Some materials are hard straight away, but it is wise to avoid chewing on that side until you can feel properly.
It varies with the material, the size of the filling, your bite and your oral hygiene. With good care, many fillings last for years, but they do not last forever and should be checked regularly.
If decay has reached the nerve and you have lingering or severe pain, you may need a root canal. Your dentist will decide based on your symptoms and an X-ray.
Routine dental care is generally safe and pain and infection are best treated rather than left. Tell your dentist you are pregnant so the plan can be adjusted.
Keep reading
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This article is for general information and does not replace a personal dental examination.